Documents / Official release
This Defense Intelligence Reference Document, DIA-08-1004-006, is dated 6 April 2010 and was prepared by the Defense Intelligence Agency's Defense Warning Office. It is one of a series of advanced technology reports produced in FY 2009 under the Advanced Aerospace Weapon System Applications Program. The report reviews electromagnetic and optical metamaterials and their uses in sub-diffraction imaging, component miniaturization, energy harvesting, optical isolators and tunable devices. It concludes that metamaterials remain academic but have great potential for aerospace applications.
From the source:Release of 2026-09-18 Incident: 4/6/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys metamaterials, engineered structures designed to control electromagnetic waves in ways ordinary materials cannot, and argues that their main aerospace value lies in unusual optical and microwave properties together with significant component miniaturization. The report reviews possible applications including sub-wavelength imaging, compact waveguides and lasers, energy harvesting, tunable absorbers, nonreciprocal devices, and switchable materials, with particular emphasis on infrared and microwave uses for sensing, power management, and payload efficiency. It notes that many of the most ambitious applications depend on the practical output of a still-nascent field, especially in optical metamaterials, where only limited demonstrations had been achieved and fabrication remained a major constraint. The document presents metamaterials as a promising advanced materials field with credible niche applications and broader long-term potential.
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prospect is not too farfetched because scattering in mid-infrared by atmospheric gases
is essentially zero. For such a remote powering scenario to be feasible, one would need
a highly efficient absorber at the specific wavelength corresponding to that of the
source. Moreover, as the space platform is moving, it is desirable that the absorption
remain high even for non-normal incidence angles.
The second application is for thermophotovoltaics (TPV) (Reference 35). Some type of
thermophotovoltaic converter will almost undoubted ly be installed on the advanced
aerospace platforms of the future. Presently even advanced ( experimental) electric cars
are using TPV cells to convert the heat from their engines into electricity. Such
converters have already been shown to be capable of increasing the range of electric
vehicles by a factor of 3. We believe that metamaterials could play an important role in
developing highly efficient TPV cells. By virtue of Kirchhoff's law, emissivity of a thermal
emitter approaches the blackbody limit only if the absorptivity approaches unity.
Moreover, wavelength-selective radiators can dramatically improve the efficiency of
current generation in a TPV ce ll if their emission spectrum is matched to the bandgap of
the TPV converter. For example, a typical TPV converter, GaSb, has the bandgap of EG
= 0. 7 eV that would be ideally suited to a wavelength-selective radiator operating in
near infrared around A= 1.7 μm.
ReHecllcn from SiC on Au Absorption vs. n, and ni for 1'.=1 3μm (ro=760cm-')
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Figure 21. (Left) Experimental Result, Reflectivity Versus Wavelength, that Inspired the Proposed
Effort: A Modestly Absorbing Material (SIC) Turns Into a "Perfect Mid-IR Absorber" When a A/4 -Thick
SiC Film Is Backed by a Metal Mirror. (Right): Theoretical Plot - Constant Reflectivity Contours Plotted
in the (Real(n), Imag(n)) Space. High material absorptivity Imag(n) is required to achieve perfect absorption
(R=O). Posed question : can a metamaterials-based semi-transparent mirror enhance absorption and result in an
almost-perfect ultra-thin absorber?
The perfect absorbers shown in Figures 17-19 may be too complex for practical
applications. Metamaterials tend to be lossy because of the large field concentration in
the metal. Therefore, work has recently started working on a new type of metamaterial
(so-called CMMs mentioned in the Introduction), that cou ld potentially make weakly
absorbing semiconductors (that is, Si in the visible) absorb much stronger. The goal
here is to make a thin (although not necessari ly a very sub-wavelength) absorber
backed up by a sheet of CMMs which would prevent reflections and result in a very high
absorption. Applications that are considered are essentially the same as for the
"perfect" absorbers described above. For example, satellites can use the Earth glow for
nighttime battery recharging. The collected power is quite high; 1 m 2 of black surface at
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 38 pages are in the text index: search them above, or from the library's search.